-LRB- CNN -RRB- -- A man accused of killing 77 people in a bomb and gun rampage in Norway last summer was sane at the time of the alleged crimes , two court-appointed psychiatric experts said in a report released Tuesday .

Anders Behring Breivik was charged last month with committing acts of terror and voluntary homicide . He is accused of killing eight people in a bomb attack in Oslo , then going to Utoya Island outside the city and systematically gunning down 69 more people , many of them teens and young adults .

The mass killing on July 22 was the single largest loss of life in Norway since World War II .

Breivik has pleaded not guilty , though he has admitted carrying out the attacks , according to the judge handling his case previously .

In November , prosecutors said psychiatrists had determined Breivik was paranoid and schizophrenic at the time of the attacks and during 13 interviews experts conducted with him afterward .

However , the court sought a second opinion because of the importance of the question of sanity to Breivik 's trial .

The two psychiatric experts recommended he spend four weeks under 24-hour psychiatric monitoring , according to court documents released in February .

The Tuesday report said Breivik was not psychotic at the time of the crimes , does not suffer from a psychiatric condition and is not mentally challenged .

`` There is a high risk for repeated violent actions , '' said the report from Terje Torrissen and Agnar Aspaas .

Breivik 's trial is set for April 16 and is expected to last up to 10 weeks . If he is convicted , his punishment will be based on the determination of his sanity . It may not be possible for him to receive the maximum punishment if he is deemed insane .

Authorities have described Breivik as a right-wing Christian extremist . A 1,500-page manifesto attributed to him posted on the Internet is critical of Muslim immigration and European liberalism , including Norway 's Labour Party .

Breivik showed some of his extremist views during a February hearing , which began with him entering court with a smile and offering up a raised , clenched-fist salute .

He insists nobody could believe that he was insane , and describes questions about his mental condition as ridiculous , his attorney , Geir Lippestad , has said .

Breivik claims the shooting rampage was a matter of self-defense , meant to save Norway from being taken over by multicultural forces and to prevent ethnic cleansing of Norwegians , Lippestad said .

The victims on Utoya Island were among 700 mostly young people attending a Labour Party camp .

CNN 's Per Nyberg contributed to this report .

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Anders Behring Breivik was not psychotic at the time of the July killings , experts say

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Breivik is accused of killing 77 people in a bomb and gun rampage

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`` There is a high risk for repeated violent actions , '' the experts say

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Breivik 's trial is set to begin April 16